Safety line systems for use with horizontal life lines to protect workers from risk of injury or death from a fall when working close to a vertical face such as when washing windows of a high rise building are well known. U.K. Patent Specification No. 1,582,201 discloses a load-transfer device for use by workers in the building and mining industries which enables a load to be moved along a path and past load bearing supports. A rotatable wheel having recesses in its periphery is adapted to slide along a single safety wire and to pass the loops of a hanger secured to a support surface.
The Barrow Hepburn Sala SAYFGLIDA.TM. life line system is another fall-arrest safety sytem which allows a worker to move safely along a horizontal plane tethered to a safety line. A link attached to a harness lanyard and travelling along a support line has a longitudinal slot formed along a side for passing the arm of a support bracket.